Memory systems and methods of managing failed memory cells of semiconductor memories

ABSTRACT

A memory system includes a memory controller configured to replace a memory block including a failed memory cell with a unit cache block of a cache memory in response to detection of the failed memory cell in the memory block. The unit cache block is smaller than a minimum size of a memory cell array capable of being blocked by an operating system, and the unit cache block has substantially the same storage capacity as the memory block.

CROSS-REFERENCE TO RELATED APPLICATIONS

This U.S. non-provisional patent application claims priority under 35U.S.C. §119 to Korean Patent Application No. 10-2013-0140131, filed onNov. 18, 2013, the entire contents of which are hereby incorporated byreference.

BACKGROUND

1. Field

Example embodiments of inventive concepts relate to memory systems, andmore particularly, to memory systems having failed memory cells andmethods of managing failed memory cells.

2. Description of Conventional Art

A dynamic random access memory DRAM or a magnetic random access memoryMRAM can be used as a main memory of a memory system.

In a DRAM, a failed memory cell may exist in a memory cell array. Ahard-failed memory cell among failed memory cells is replaced with aspare memory cell through a repair process.

A soft-failed memory cell among failed memory cells can be divided intoa faulty memory cell and a weak memory cell. In the case that a faultymemory cell exists in a memory cell array, a masking off operation ofinhibiting an access operation with respect to a corresponding memorycell is desired. In the case that a weak memory cell exists in a memorycell array, since its operation is similar to an operation of a normalmemory cell having relatively high reliability of data access, arelatively frequent refresh operation may be desired.

However, a frequent refresh operation of a weak memory cell may increasepower consumption.

A unit of memory that is masked off when a faulty memory cell or a weakmemory cell occurs may be a page frame unit, which includes a pluralityof memory blocks of a memory cell array. However, masking off aplurality of memory blocks due to one failed memory cell results inwasted memory capacity.

SUMMARY

At least some example embodiments of inventive concepts provide methodsof managing failed memory cells of semiconductor memories. When at leastone failed memory cell is detected in a memory block of a memory cellarray, at least one unit cache block of a cache memory is assigned as areplacement for the memory block. The memory block including the failedmemory cell is then replaced (e.g., permanently replaced) with the unitcache block. The at least one unit cache block is smaller than a pageframe unit of the memory cell array, and the page frame unit is thesmallest unit capable of being blocked by an operating system. The atleast one unit cache block also has the same memory capacity as astorage capacity of the memory block.

At least one example embodiment provides a method of managing failedmemory of a semiconductor memory. According to at least this exampleembodiment, the method includes: assigning at least one unit cache blockas a replacement for at least one memory block of a page frame unit of amemory cell array in response to detection of at least one failed memorycell of the at least one memory block, the at least one unit cache blockbeing smaller than the page frame unit of the memory cell array, the atleast one unit cache block having a same storage capacity as the atleast one memory block, and the page frame unit being a minimum size ofthe memory cell array capable of being blocked by an operating system;and replacing the at least one memory block including the at least onefailed memory cell with the at least one unit cache block.

According to at least some example embodiments, the at least one failedmemory cell may be a soft-failed memory cell, a faulty memory cell or aweak memory cell.

The method may further include: testing the memory cell array to detectthe at least one failed memory cell. The testing of the memory cellarray may be performed prior to operation of the operating system.Alternatively, the testing of the memory cell array may be performedperiodically during access of a memory including the memory cell arrayand after an operation of the operating system is completed.

The at least one unit cache block replacing the at least one memoryblock may be locked in software and no longer usable as cache memory.

The at least one unit cache block may be part of a lowest level cachememory among a plurality of cache memories utilized by the operatingsystem.

The at least one memory block may not be recognized as a failed memoryblock by a processor executing the operating system.

The memory cell array may be part of a dynamic random access memory(DRAM) being used as a main memory.

The memory cell array may be part of a magnetic random access memory(MRAM) having a plurality of spin-transfer torque MRAM (STT MRAM) cellsbeing used as a main memory.

At least one other example embodiment provides a memory systemincluding: a memory including a memory cell array, the memory cell arrayincluding a plurality of memory blocks, each of the plurality of memoryblocks including a plurality of memory cells; a cache memory including aplurality of unit cache blocks, each of the plurality of unit cacheblocks being smaller than a page frame unit of the memory cell array,the page frame unit being a minimum size of the memory cell arraycapable of being blocked by an operating system, and the plurality ofunit cache blocks having a same storage capacity as the plurality ofmemory blocks; and a memory controller configured to replace a memoryblock having a failed memory cell with a corresponding one of theplurality of unit cache blocks in response to detection of the failedmemory cell in the memory block.

According to at least some example embodiments, the corresponding one ofthe plurality of unit cache blocks may be locked in software topermanently replace the memory block having the failed memory cell. Whenan address for accessing the memory block having the failed memory cellis applied to the memory controller, the corresponding one of theplurality of unit cache blocks may be accessed instead of the memoryblock having the failed memory cell.

At least one other example embodiment provides a memory systemincluding: a memory controller configured to replace a memory blockhaving a failed memory cell with a unit cache block of a cache memory inresponse to detection of the failed memory cell in the memory block, theunit cache block being smaller than a minimum size of a memory cellarray capable of being blocked by an operating system, and the unitcache block having substantially the same storage capacity as the memoryblock.

According to at least some example embodiments, the failed memory cellmay be a soft-failed memory cell, a faulty memory cell or a weak memorycell. The unit cache block replacing the memory block may be locked insoftware and no longer usable as a cache memory. The memory controllermay be configured to access the unit cache block instead of the memoryblock having the failed memory cell in response to an address foraccessing the memory block having the failed memory cell.

The memory system may further include: a memory including the memorycell array having a plurality of memory blocks, the plurality of memoryblocks including the memory block with the failed memory cell; and thecache memory including the unit cache block.

BRIEF DESCRIPTION OF THE FIGURES

Example embodiments of inventive concepts will be described below inmore detail with reference to the accompanying drawings. Exampleembodiments of inventive concepts may, however, be embodied in differentforms and should not be constructed as limited to the exampleembodiments set forth herein. Rather, these example embodiments areprovided so that this disclosure will be thorough and complete, and willfully convey the scope of the inventive concept to those skilled in theart. Like numbers refer to like elements throughout.

FIG. 1 is a block diagram of a memory system according to an exampleembodiment of inventive concepts.

FIG. 2 is a drawing illustrating an example page frame unit of a memoryin accordance with FIG. 1.

FIG. 3 is a drawing illustrating an example replacement of a memoryblock unit in accordance with FIG. 1.

FIG. 4 is a flow chart illustrating an example replacement operationwhen a booting operation is performed in accordance with FIG. 1.

FIG. 5 is a flow chart illustrating an example replacement operationwhen a processing operation is performed in accordance with FIG. 1.

FIG. 6 is a flow chart of an example access replacement operation inaccordance with FIG. 1.

FIG. 7 is a block diagram of a memory system in accordance with anotherexample embodiment.

FIG. 8A through 8D are drawings illustrating example applications ofexample embodiments applied to a memory system having variousinterfaces.

FIG. 9 is a drawing illustrating an example application of exampleembodiments of inventive concepts applied to a memory system stackedthrough a through-silicon-via (TSV).

FIG. 10 is a block diagram illustrating an example application ofexample embodiments of inventive concepts applied to a computing device.

FIG. 11 is a block diagram illustrating an example application ofexample embodiments of inventive concepts applied to a smart phone.

FIG. 12 is a block diagram illustrating an example application ofexample embodiments of inventive concepts applied to a data processingsystem including system-on-chip (SOC).

FIG. 13 is a block diagram illustrating an example application ofexample embodiments of inventive concepts applied to another dataprocessing system.

FIG. 14 is a block diagram illustrating an example application ofexample embodiments of inventive concepts applied to still another dataprocessing system.

DETAILED DESCRIPTION

Example embodiments will now be described more fully with reference tothe accompanying drawings. Inventive concepts may, however, be embodiedin many different forms and should not be construed as being limited tothe exemplary embodiments set forth herein; rather, these embodimentsare provided so that this disclosure will be thorough and complete, andwill fully convey the concept of the invention to those skilled in theart.

In the drawings, like reference numerals refer to like elements, andredundant descriptions thereof will be omitted. Furthermore, variouselements and regions in the drawings are schematically drawn. Thus, theinventive concept is not limited by a relative size or distance drawn inthe attached drawings.

It will be understood that, although the terms first and second etc. maybe used herein to describe various elements, components, regions, layersand/or sections, these elements, components, regions, layers and/orsections should not be limited by these terms. These terms are only usedto distinguish one element, component, region, layer or section fromanother element, component, region, layer or section. For example, afirst element could be termed a second element, and similarly, a secondelement could be termed a first element without departing from theteachings of the example embodiment.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention. Asused herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises”and/or “comprising,” or “includes” and/or “including” when used in thisspecification, specify the presence of stated features, regions,integers, steps, operations, elements, and/or components, but do notpreclude the presence or addition of one or more other features,regions, integers, steps, operations, elements, components, and/orgroups thereof.

In the drawings, for example, illustrated shapes may be deformedaccording to fabrication technology and/or tolerances. Therefore, theexample embodiments of inventive concepts are not limited to certainshapes illustrated in the present specification, and may includemodifications of shapes caused in fabrication processes.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this invention belongs. It will befurther understood that terms, such as those defined in commonly useddictionaries, should be interpreted as having a meaning that isconsistent with their meaning in the context of the relevant art andwill not be interpreted in an idealized or overly formal sense unlessexpressly so defined herein.

As used herein, the term “and/or” includes any and all combinations ofone or more of the associated listed items. Expressions such as “atleast one of,” when preceding a list of elements, modify the entire listof elements and do not modify the individual elements of the list.

Inventive concepts will be described more fully hereinafter withreference to the accompanying drawings, in which example embodiments areshown. Inventive concepts may, however, be embodied in many differentforms and should not be construed as limited to the example embodimentsset forth herein. Rather, these example embodiments are provided so thatthis disclosure will be thorough and complete, and will fully convey thescope of the inventive concept to those skilled in the art. In thedrawings, the size and relative sizes of layers and regions may beexaggerated for clarity. Like numbers refer to like elements throughout.

FIG. 1 is a block diagram of a memory system in accordance with anexample embodiment of inventive concepts.

Referring to FIG. 1, a memory system includes a memory 100, a memorycontroller 200, and a cache memory 300.

The cache memory 300 is connected to the memory controller 200 through abus B30.

The cache memory 300 is connected to a processor 400 such as a CPU or amicroprocessor through a bus B20.

The cache memory 300 may include a L1 cache 310, a L2 cache 320 and a L3cache 330 according to a cache function level.

The memory 100 can function as a main memory in a system of FIG. 1 andcan be constituted by a DDR2, 3, 4 DRAM (dynamic random access memory)or a MRAM (magnetic random access memory).

The memory 100 includes a memory cell array having multiple memoryblocks. The memory block is constituted by a plurality of memory cells.In the case that the memory cell is a DRAM cell, a refresh operation fordata retention is performed. In the case that the memory cell is a MRAMcell, since the stored data is maintained even when power is turned off,a refresh operation is not needed.

The L3 cache 330 which is a cache memory of the lowest level of thecache memory 300 can be embodied by one of a SRAM (static random accessmemory), a DRAM, a MRAM and a PRAM (phase change random access memory).The L3 cache 330 can have a plurality of unit cache blocks smaller thana page frame unit of a memory cell array of the memory 100 being blockedby an operating system OS and having the same memory capacity as astorage capacity of the memory block.

When at least one failed memory cell is detected in the memory blocks ofthe memory 100, the memory controller 200 replaces a correspondingmemory block including the defective memory cell with the unit cacheblock in the L3 cache 330.

The replaced unit cache block is locked and cannot perform a function asa cache memory any more. The replaced unit cache block functions as thememory blocks of the memory 100. In the case that an access to thecorresponding memory block including the failed memory cell isrequested, an access to the memory block is blocked and the unit cacheblock is accessed. Thus, when a data write operation is performed, writedata is written in the unit cache block. When a data read operation isperformed, read data is read from the unit cache block.

Since a capacity that spares the unit cache block in the cache memory isfar smaller than a page frame unit of a memory cell array being blockedby the operating system OS, a waste of a maim memory is minimized. Toreduce a memory size being masked, a memory block smaller than the pageframe unit is masked off without masking off the page frame unit in thememory 100 and the unit cache block is sacrificed instead.

FIG. 2 is a drawing illustrating a page frame unit of a memory inaccordance with FIG. 1.

Referring to FIG. 2, the memory cell array of the memory 100 includes aplurality of memory blocks. The memory cell array may include aplurality of page frame units 110-1, 110-2, . . . , 110-n. One pageframe unit includes a plurality of memory blocks BL1, BL2, . . . , BLn.One memory block may have a memory capacity of 64 byte (64 B) and onepage frame unit may have a memory capacity of 4 kilobyte (4 kB).

Thus, a memory capacity of one page frame unit is far greater than amemory capacity of one memory block.

In the case that a failed memory cell (F/W MC) indicating a faultymemory cell or a weak memory cell exists in the memory cell array of thememory 100 of FIG. 1, an operating system OS of the processor 400 masksoff the whole page frame unit 110-1 including the F/W MC. That is, theminimum masking off unit of the operating system OS is a page frame unit110-1. Thus, in the case of FIG. 2, although F/W MC exists only in thesecond memory block BL2, the remaining memory blocks BL1, BL3, . . . ,BLn are all masked off.

Since a masking off of a page frame unit is performed, it is wasteful ofmain memories. To solve a problem of a waste of memory, in at least oneexample embodiment of inventive concepts, replacement of a memory blockunit is performed using a cache memory. Thus, only a memory blockincluding F/W MC is masked off by an operation of the memory controller200.

Since a plurality of memory blocks is not all masked off due to onefailed memory cell, a memory can be saved.

FIG. 3 is a drawing illustrating an example replacement of a memoryblock unit in accordance with FIG. 1.

Referring to FIG. 3, if at least one F/W MC exist in the first memoryblock BL1, the first memory block BL1 is replaced with a unit cacheblock 330-2 in the cache memory 300. If at least one F/W MC exist in thenth memory block BLn, the nth memory block BLn is replaced with a unitcache block 330-n in the cache memory 300. Here, a memory capacity ofthe memory block may be equal to or smaller than a memory capacity ofthe unit cache block. For example, although it is not limited, a memorycapacity of the unit cache block may be assigned 64 B. The unit cacheblock which replaces the memory block is locked in software or firmware.The locked unit cache block functions as the memory block and does notperform a function of the cache memory any more.

The unit cache block is locked by the memory controller 200 or theprocessor 400 receiving a request of the memory controller 200.

A unit cache block 330-1 may include a data area AR2 for storing dataand a tag area AR1 for storing address information of data stored in thedata area AR2.

FIG. 4 is a flow chart illustrating an example replacement operationwhen a booting operation is performed in accordance with FIG. 1.

In a step S400, booting sequences are executed. The booting sequencesinclude turning on a cache memory.

In a step S410, a list of memory blocks having F/W MCs is imported. Whena booting operation is performed, the memory controller 200 can transmitthe list to the processor 400. The list may be address information ofthe memory blocks having F/W MCs.

In a step S420, a unit cache block covering a memory block having F/WMCs is reserved and locked in the cache memory. The unit cache blocklocked by performing the step S420 functions as a memory blockcorresponding to a DRAM or a MRAM. The memory block having F/W MCs ismasked off to be permanently access-inhibited.

If an operation of the step S420 is completed, in a step S430, otherbooting sequences are resumed.

An operation of FIG. 4 can be performed by the memory controller 200 orcooperation of the memory controller 200 and the processor 400. Exampleembodiments of inventive concepts are not limited thereto.

FIG. 5 is a flow chart illustrating an example replacement operationwhen a processing operation is performed in accordance with FIG. 1.

In a step S500, it is checked whether a failed memory cell, that is, F/WMC is detected or not. The check operation may be periodically executedwhile a system operates or may be executed when an event occurs.

In a step S510, a physical block address of memory blocks having F/W MCis identified. Accordingly, a physical block address of memory blockshaving F/W MC is determined. The physical block address is an addresscorresponding to a logical block address and means an address of amemory block substantially located in the memory cell array.

In a step S520, a unit cache block covering a memory block having F/WMCs is reserved and locked in the cache memory. The unit cache blocklocked by performing the step S520 functions as a memory blockcorresponding to a main memory. The memory block having F/W MCs ismasked off to be permanently access-inhibited.

If a replacement operation of the step S520 is completed, in a stepS530, a processing operation is resumed.

An operation of FIG. 5 can be performed by the memory controller 200 orcooperation of the memory controller 200 and the processor 400. Exampleembodiments of inventive concepts are not limited thereto.

According to FIGS. 4 and 5, after a memory cell array is tested whichincludes multiple memory blocks constituted by a plurality of memorycells, if at least one failed memory cell are detected in the memoryblocks, at least one unit cache block having a memory capacity smallerthan a page frame unit of the memory cell array being blocked by aminimum unit by an operating system and is equal or substantially equalto a storage capacity of the memory block is assigned to a cache memory.

The unit cache block permanently replaces a corresponding memory blockincluding the failed memory cell.

FIG. 6 is a flow chart of an example access replacement operation inaccordance with FIG. 1.

In a step S600, it is checked whether a request for accessing a failedmemory cell, that is, F/W MC occurs or not. Since the processor 400cannot recognize that a memory block is replaced with a correspondingunit cache block, the processor 400 can provide a request for accessingF/W MC to the memory controller 200.

In a step S610, after masking off memory blocks having F/W MC, thememory controller 200 accesses a unit cache block corresponding to thememory blocks having F/W MC. The unit cache block functions as a memoryblock for reading or writing data.

In a step S620, in the case of a read operation, data stored in the unitcache block is read. In the case of a write operation, write data iswritten in the unit cache block.

FIG. 7 is a block diagram of a memory system in accordance with anotherexample embodiment of inventive concepts.

Referring to FIG. 7, a constitution of FIG. 7 is the same as theconstitution of FIG. 1, except that the cache memory 300 is built in theprocessor 400.

A memory system includes the memory 100, the memory controller 200 andthe processor 400 having the cache memory 300.

The cache memory 300 is connected to the memory controller 200 throughthe bus B30.

The cache memory 300 performs a data communication with the processor400 through an internal bus.

The cache memory 300 may include at least one of a L1 cache, a L2 cacheand a L3 cache according to a cache function level.

The memory 100 can function as a main memory in the memory system ofFIG. 7 and may be constituted by DDR2, 3, 4, a SDRAM or a MRAM.

The memory 100 includes a memory cell array having multiple memoryblocks. The memory block is constituted by a plurality of memory cells.In the case that the memory cell is a DRAM cell, a refresh operation fordata retention is performed. In the case that the memory cell is a MRAMcell, since the stored data is maintained even when power is turned off,a refresh operation is not needed.

The cache memory 300 can be embodied by one of a SRAM, a DRAM, a MRAMand a PRAM. The cache memory 300 may have a plurality of unit cacheblocks having a memory capacity smaller than a page frame unit of amemory cell array of the memory 100 being blocked by an operating systemOS and equal to a storage capacity of the memory block.

When at least one failed memory cell is detected in the memory blocks ofthe memory 100, the memory controller 200 replaces a correspondingmemory block including the defective memory cell with the unit cacheblock in the cache memory 300.

The replaced unit cache block is locked and cannot perform a function asa cache memory any more. The replaced unit cache block functions as thememory blocks of the memory 100. In the case that an access to thecorresponding memory block including the failed memory cell isrequested, an access to the memory block is blocked and the unit cacheblock is accessed. Thus, when a data write operation is performed, writedata is written in the unit cache block. When a data read operation isperformed, read data is read from the unit cache block.

A capacity that the unit cache block in the cache memory is sacrificedis far smaller than the page frame unit of the memory cell array beingblocked by the operating system OS.

In the case that a main memory is constituted by a DRAM, if a memoryblock including a weak memory cell is replaced with the unit cacheblock, a refresh performance is improved. That is, since a refreshoperation frequently being performed for the weak memory cells isminimized or reduced, power consumption of the memory system is reduced.

A test for determining a failed memory cell in the memory block may beperformed periodically or when a booting operation is performed byapplying a mode register set (MRS) signal to the memory controller 200and the memory 100.

In FIG. 7, the memory 100 can be embodied by a nonvolatile memory. Thenonvolatile memory may be, for example, an electrically erasableprogrammable read-only memory (EEPROM), a flash memory, a magneticrandom access memory (MRAM), a spin-transfer torque (STT) MRAM, aconductive bridging RAM (CBRAM), a ferroelectric RAM (FeRAM), a phasechange RAM (PRAM) which is called an ovonic unified memory (OUM), aresistive RAM (RRAM), a nanotube RRAM, a polymer RAM (PoRAM), a nanotubefloating gate memory (NFGM), a holographic memory, a molecularelectronics memory device, or an insulator resistance change memory.

FIG. 8A through 8D are drawings illustrating example applications ofexample embodiments of inventive concepts applied to a memory systemhaving various interfaces.

Referring to FIG. 8A, a memory system is constituted by a controller1000 and a memory device 2000. The controller 1000 is constituted by acontrol unit 1100 and an input and output circuit 1200. The memorydevice 2000 is constituted by a DRAM core including a sensing and latchcircuit 2110, and an input and output circuit 2200. The input and outputcircuit 1200 of the controller 1000 includes an interface transmitting acommand, a control signal, an address and a data strobe DQS to thememory device 2000 and transmitting and receiving data DQ. The DRAM core2110 may be embodied by the memory 100 of FIG. 1.

Thus, in the case that a memory block including a failed memory cellexists, the corresponding memory block may be replaced with a unit cacheblock of a cache memory.

With regard to FIGS. 8A through 8D, one or more of the controller 1000,the control unit 1100, the input and output circuit 1200, and the inputand output circuit 2200 may be at least partially implemented ashardware, firmware, hardware executing software or any combinationthereof. When implemented as hardware, such hardware may include, interalia, one or more Central Processing Units (CPUs), digital signalprocessors (DSPs), application-specific-integrated-circuits (ASICs),field programmable gate arrays (FPGAs) computers or the like configuredas special purpose machines to perform the functions of the one or moreof the controller 1000, the control unit 1100, the input and outputcircuit 1200, and/or the input and output circuit 2200. CPUs, DSPs,ASICs and FPGAs may generally be referred to as processors and/ormicroprocessors.

Referring to FIG. 8B, the input and output circuit 1200 of thecontroller 1000 includes an interface transmitting a chip selectionsignal CS and an address by one packet and transmitting and receivingdata DQ.

Referring to FIG. 8C, the input and output circuit 1200 of thecontroller 1000 includes an interface transmitting a chip selectionsignal CS, an address and write data (wData) by one packet and receivingread data (rData).

Referring to FIG. 8D, the input and output circuit 1200 of thecontroller 1000 includes an interface transmitting and receiving acommand, an address and data DQ and receiving a chip selection circuitCS.

In FIGS. 8B through 8D, in the case that a memory block including afailed memory cell exists, the corresponding memory block may bereplaced with a unit cache block of a cache memory according to acontrolling operation of the controller 1000.

FIG. 9 is a drawing illustrating an example application of exampleembodiments of inventive concepts applied to a memory system stackedthrough a through-silicon-via (TSV).

Referring to FIG. 9, an interface chip 3010 is located on the lowestlayer and memory chips 3100, 3200, 3300 and 3400 are located on theinterface chip 3010. The memory chips 3100, 3200, 3300 and 3400 includesensing and latch circuits 3601, 3602, 3603 and 3604 respectively. Thememory chips 3100, 3200, 3300 and 3400 are connected to one anotherthrough micro bumps (uBump) 3500 or through silicon via (TSV). Thenumber of stacked memory chips may be one or more.

The memory chips 3100, 3200, 3300 and 3400 can be embodied by the memory100 of FIG. 1.

FIG. 10 is a block diagram illustrating an example application ofexample embodiments of inventive concepts applied to a computing device.

Referring to FIG. 10, a computing device may include a memory system4500 including a DRAM 4520 and a memory controller 4510. The memorysystem 4500 can be embodied like FIG. 1.

The computing device may include an information processing device or acomputer. For example, the computing device may include the memorysystem 4500 and a modem 4400, a CPU 4100, a RAM 4200, a user interface4300 that are electrically connected to a system bus 4250. The memorysystem 4500 may store data processed by the CPU 100 or data input fromthe outside.

The computing device can be applied to a solid state disk (SSD), acamera image processor and an application chipset. The memory system4500 can be constituted by a SSD. In this case, the computing device canstably and reliably store large amounts of data in the memory system4500.

The DRAM 4520 constituting the memory system 4500 can be embodied by thememory 100 of FIG. 1. Thus, a waste of memory can be improved.

The memory controller 4510 can channel-independently apply a command, anaddress, data or a control signal to the DRAM 4520.

The CPU 4100 functions as a host and controls the whole operation of thecomputing device.

A host interface between the CPU 4100 and the memory controller 4510includes various protocols for performing a data exchange between thehost and the memory controller 4500. The memory controller 4510 may beconfigured to communicate with the host or the outside through at leastone of various interface protocols such as a universal serial bus (USB),a multimedia card (MMC) interface, a PCI express interface, a serialATA, a parallel ATA, a small computer system interface (SCSI), a serialattached SCSI (SAS) interface, an enhanced small disk interface (ESDI)and an integrated drive electronics (IDE) interface.

The computing device may be provided as one of various constituentelements of electronic devices such as a computer, an ultra mobile PC(UMPC), a digital picture player, a digital video recorder, a digitalvideo player, a storage constituting a data center, a device that cantransmit and receive information in a wireless environment, one ofvarious electronic devices constituting a home network, one of variouselectronic devices constituting a computer network, one of variouselectronic devices constituting a telematics network, and one of variousconstituent elements constituting a RFID device or a computing system.

The DRAM 4520 chip or the CPU 4100 can be mounted separately or togetherusing various types of packages such as PoP (package on package), ballgrid array (BGA), chip scale package (CSP), plastic leaded chip carrier(PLCC), plastic dual in-line package (PDIP), die in waffle pack, die inwafer form, chip on board (COB), ceramic dual in-line package (CERDIP),plastic metric quad flat pack (MQFP), thin quad flat pack (TQFP), smalloutline (SOIC), shrink small outline package (SSOP), thin small outline(TSOP), thin quad flatpack (TQFP), system in package (SIP), multi chippackage (MCP), wafer-level fabricated package (WFP) and wafer-levelprocessed stack package (WSP).

FIG. 11 is a block diagram illustrating an example application ofexample embodiments of inventive concepts applied to a smart phone.

Referring to FIG. 11, a block diagram of an important part of a cellularphone such as a smart phone with a built-in DRAM is illustrated. A smartphone may include an antenna (ATN) 501, an analog front end block (AFE)503, analog-digital converting circuits (ADC1) 505 and (ADC2) 519,digital-analog converting circuits (DAC1) 507 and (DAC2) 517, a baseband block (BBD) 509, a speaker (SPK) 521, a liquid crystal display(LCD) 523, a mike (MIK) 525, and an input key (KEY) 527. Although notillustrated, the analog front end block (AFE) 503 is constituted by anantenna switch, a band pass filter, all sorts of amplifiers, a poweramplifier, a phase locked loop (PLL), a voltage control oscillator, anorthogonal demodulator, and an orthogonal modulator to execute atransmit/receive of a radio wave. The base band block 509 may include asignal processing circuit (SGC) 511, a baseband processor (BP) 513, anda DRAM 515.

An operation of the smart phone of FIG. 11 is described. In the casethat an image including voice and character information is received, aradio wave input from an antenna is input to the analog-digitalconverting circuit (ADC1) 505 through the analog front end block (AFE)503 to be waveform-equalized and converted from an analog waveform intoa digital waveform. An output signal of the ADC1 505 is input to thesignal processing circuit (SGC) 517 in the base band block 509 to bevoice and image-processed and the voice signal is transmitted to thespeaker 521 through the digital-analog converting circuit (DAC2) 517 andthe image signal is transmitted to the liquid crystal display (LCD) 523.

In the case of transmitting a voice signal, a signal input from the mike525 is input to the signal processing circuit (SGC) 511 through theanalog-digital converting circuit (ADC2) 519 to be voice-processed. Anoutput of the SGC 511 is transmitted from the digital-analog convertingcircuit (DAC1) 507 to the antenna 501 through the analog front end block(AFE) 503. In the case of transmitting character information, a signalinput from the input key 527 is transmitted to the antenna 501sequentially through the base band block 509, the digital analogconverting circuit 507 and the analog front end block (AFE) 503.

In FIG. 11, the DRAM 515 can be embodied by the memory 100 of FIG. 1. Inthis case, the DRAM 515 may be accessed by the base band processor 513through a first channel and may also be accessed by an applicationprocessor not illustrated through a second channel. That is, one memorychip can be shared to be used by two processors.

Although the DRAM 515 is mounted in FIG. 11, in another case, a DRAM canbe replaced with a MRAM.

A volatile memory device such as a SRAM or a DRAM loses its stored datawhen its power is interrupted.

A nonvolatile memory device such as a magnetic random access memory(MRAM) retains its stored data even after its power is interrupted.Thus, to maintain stored data even when power is poor or power is cutoff, a nonvolatile memory device is preferably used to store data.

In the case that s spin transfer torque magneto resistive random accessmemory (STT-MRAM) constitutes a memory, an advantage of a MRAM may beadded to an advantage of FIG. 1.

The STT-MRAM may include a magnetic tunnel junction (MTJ) device and aselection transistor. The MTJ device may basically include a fixedlayer, a free layer and a tunnel layer formed between the fixed layerand the free layer. A magnetization direction of the fixed layer isfixed and a magnetization direction of the free layer may be the same asor reverse to the magnetization direction of the fixed layer dependingon a condition.

FIG. 12 is a block diagram illustrating an example application ofexample embodiments of inventive concepts applied to a data processingsystem including a system-on-chip (SOC).

Referring to FIG. 12, a data processing system 2000 may include a SOC150, an antenna 201, an RF transceiver 203, an input device 205, and adisplay 207.

The RF transceiver 203 can transmit or receive a wireless signal throughthe antenna 201. The RF transceiver 203 can convert a wireless signalreceived through the antenna 201 into a signal that can be processed inthe SOC 150.

Thus, the SOC 150 can process a signal output from the RF transceiver203 and can transmit the processed signal to the display 207. The RFtransceiver 203 can convert a signal output from the SOC 150 into awireless signal and can output the converted signal to an externaldevice through the antenna 201.

The input device 205 can be inputted with a control signal forcontrolling an operation of the SOC 150 or data to be processed by theSOC 150. The input device 205 can be embodied by a pointing device suchas a touch pad and a computer mouse, a keypad, or a keyboard.

Since the SOC 150 in the data processing system of FIG. 12 can includethe memory system of FIG. 1, a waste of a memory is minimized and powerconsumption can be reduced.

FIG. 13 is a block diagram illustrating an example application ofexample embodiments of inventive concepts applied to another dataprocessing system.

Referring to FIG. 13, a data processing system 3000 can be embodied in apersonal computer (PC), a network server, a tablet PC, a net-book, ane-reader, a personal digital assistant (PDA), a portable multimediaplayer (PMP), a MP3 player, or a MP4 player.

The data processing system 3000 includes a SOC 150, a memory device 301,a memory controller 302 that can control a data processing operation ofthe memory device 301, a display 303 and an input device 304.

The SOC 150 receives data input through the input device 304. Datastored in the memory device 301 can be displayed through the display 303according to a control operation and a processing operation. The inputdevice 304 can be embodied by a pointing device such as a touch pad anda computer mouse, a keypad, or a keyboard. The SOC 150 can control thewhole operation of the data processing system 3000 and can control anoperation of the memory controller 302.

The memory controller 302 that can control an operation of the memorydevice 301 can be embodied as a part of the SOC 150 or can be embodiedto be independent of the SOC 150.

Since the data processing system 3000 of FIG. 13 includes the memorysystem of FIG. 1, a waste of a memory is minimized and power consumptioncan be reduced.

The data processing system 3000 of FIG. 13 can be changed or expanded toone of various constituent elements of an electronic device, such as anultra mobile PC (UMPC), a workstation, a net-book, a personal digitalassistants (PDA), a portable computer, a web tablet, a tablet computer,a wireless phone, a mobile phone, a smart phone, an e-book, a portablemultimedia player (PMP), a portable game machine, a navigation device, ablack box, a digital camera, a digital multimedia broadcasting (DMB)player, a three dimensional television, a smart television, a digitalaudio recorder, a digital audio player, a digital picture recorder, adigital picture player, a digital video recorder, a digital videoplayer, a storage constituting a data center, a device that can transmitand receive information in a wireless environment, one of variouselectronic devices constituting a home network, one of variouselectronic devices constituting a computer network, one of variouselectronic devices constituting a telematics network, and one of variousconstituent elements constituting a RFID device or a computing system.

FIG. 14 is a block diagram illustrating an example application ofexample embodiments of inventive concepts applied to still another dataprocessing system.

A data processing system 4000 including a SOC 150 illustrated in FIG. 14can be embodied by an image processing device, for example, a digitalcamera, or a mobile phone or a smart phone fitted with a digital camera.

The data processing system 4000 includes a memory device 401 and amemory controller 402 that can control a data processing operation, forexample, a write operation or a read operation. The data processingsystem 4000 further includes an image sensor 403 that can perform afunction such as an input device and a display 404.

The image sensor 403 of the data processing system 4000 converts anoptical image into digital signals and the converted digital signals aretransmitted to the SOC 150 or the memory controller 402. According to acontrol of the SOC 150, the converted digital signals can be displayedthrough the display 404 or can be stored in the memory device 401through the memory controller 402. Data stored in the memory device 401is displayed through the display 403 according to a control of thememory controller 402.

Since the data processing system 4000 of FIG. 14 includes the memorysystem of FIG. 1 and is replaced by a memory block unit, a waste of amemory is minimized or reduced. Since a memory block including a weakmemory cell is access-inhibited, power consumption of the memory systemis reduced.

As discussed herein, a memory controller may be at least partiallyimplemented as hardware, firmware, hardware executing software or anycombination thereof. When implemented as hardware, such hardware mayinclude, inter alia, one or more Central Processing Units (CPUs),digital signal processors (DSPs),application-specific-integrated-circuits (ASICs), field programmablegate arrays (FPGAs) computers or the like configured as special purposemachines to perform the functions of the memory controller. CPUs, DSPs,ASICs and FPGAs may generally be referred to as processors and/ormicroprocessors.

Although some example embodiments of inventive concepts have been shownand described, it will be appreciated by those skilled in the art thatchanges may be made in these embodiments without departing from theprinciples and spirit of the inventive concepts, the scope of which isdefined in the appended claims and their equivalents. Therefore, theabove-disclosed subject matter is to be considered illustrative, and notrestrictive.

What is claimed is:
 1. A method of managing failed memory of asemiconductor memory, the method comprising: assigning at least one unitcache block as a replacement for at least one memory block of a pageframe unit of a memory cell array in response to detection of at leastone failed memory cell of the at least one memory block, the at leastone unit cache block being smaller than the page frame unit of thememory cell array, the at least one unit cache block having a samestorage capacity as the at least one memory block, and the page frameunit being a minimum size of the memory cell array capable of beingblocked by an operating system; and replacing the at least one memoryblock including the at least one failed memory cell with the at leastone unit cache block.
 2. The method of claim 1, wherein the at least onefailed memory cell is a soft-failed memory cell.
 3. The method of claim1, wherein the at least one failed memory cell is a faulty memory cell.4. The method of claim 1, wherein the at least one failed memory cell isa weak memory cell.
 5. The method of claim 1, further comprising:testing the memory cell array to detect the at least one failed memorycell.
 6. The method of claim 5, wherein the testing of the memory cellarray is performed prior to operation of the operating system.
 7. Themethod of claim 5, wherein the testing of the memory cell array isperformed periodically during access of a memory including the memorycell array and after an operation of the operating system is completed.8. The method of claim 1, wherein the at least one unit cache blockreplacing the at least one memory block is locked in software and nolonger usable as cache memory.
 9. The method of claim 1, wherein the atleast one unit cache block is part of a lowest level cache memory amonga plurality of cache memories utilized by the operating system.
 10. Themethod of claim 1, wherein the at least one memory block is notrecognized as a tailed memory block by a processor executing theoperating system.
 11. The method of claim 1, wherein the memory cellarray is part of a dynamic random access memory (DRAM) being used as amain memory.
 12. The method of claim 1, wherein the memory cell array ispart of a magnetic random access memory (MRAM) having a plurality ofspin-transfer torque MRAM (STT MRAM) cells being used as a main memory.13. A memory system comprising: a memory including a memory cell array,the memory cell array including a plurality of memory blocks, each ofthe plurality of memory blocks including a plurality of memory cells; acache memory including a plurality of unit cache blocks, each of theplurality of unit cache blocks being smaller than a page frame unit ofthe memory cell array, the page frame unit being a minimum size of thememory cell array capable of being blocked by an operating system, andthe plurality of unit cache blocks having a same storage capacity as theplurality of memory blocks; and a memory controller configured toreplace a memory block having a failed memory cell with a correspondingone of the plurality of unit cache blocks in response to detection ofthe failed memory cell in the memory block.
 14. The memory system ofclaim 13, wherein the corresponding one of the plurality of unit cacheblocks is locked in software to permanently replace the memory blockhaving the failed memory cell.
 15. The memory system of claim 14,wherein when an address for accessing the memory block having the failedmemory cell is applied to the memory controller, the corresponding oneof the plurality of unit cache blocks is accessed instead of the memoryblock having the failed memory cell.
 16. A memory system comprising: amemory controller configured to replace a memory block having a failedmemory cell with a unit cache block of a cache memory in response todetection of the failed memory cell in the memory block, the unit cacheblock being smaller than a minimum size of a memory cell array capableof being blocked by an operating system, and the unit cache block havingsubstantially the same storage capacity as the memory block.
 17. Thememory system of claim 16, wherein the failed memory cell is asoft-failed memory cell, a faulty memory cell or a weak memory cell. 18.The memory system of claim 16, wherein the unit cache block replacingthe memory block is locked in software and no longer usable as cachememory.
 19. The memory system of claim 16, wherein the memory controlleris further configured to access the unit cache block instead of thememory block having the failed memory cell in response to an address foraccessing the memory block having the failed memory cell.
 20. The memorysystem of claim 16, further comprising: a memory including the memorycell array having a plurality of memory blocks, the plurality of memoryblocks including the memory block having the failed memory cell; and thecache memory including the unit cache block.